Thanks ... I see what you mean now ... you have to select it, before double clicking, otherwise you navigate forwards ... looks like you have found another bug to me.

And I think he's right:

Navigate to some node within the library in grid view, e.g. Genres.
Now, single click any [Genre] to have matching albums listed.
And now, *try* to double click another [Genre] below the expanded albums list.

You can't - which is, I believe, because of using some 'mousedown' or 'mouseup' event instead of 'click'... Or something completely different, just guessing to be honest.